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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

III-V nitride semiconductor-based ultraviolet photodetectors

Yang, Bo, active 21st century 14 May 2015 (has links)
Visible-blind and solar-blind ultraviolet photodetectors based on GaN/AlGaN were designed, fabricated, and characterized for commercial and military applications. High performance back-illuminated solar-blind MSM achieved external quantum efficiency of ~48%. The dark current of 40x40μm MSM was less than the instrument measurement limitation of 20fA for a bias <100V. No photoconductive gain was observed. With an n-type doped high-Al ratio "window" Al₀.₆Ga₀.₄N layer, back-illuminated solar-blind p-i-n photodiode achieved a quantum efficiency of ~55% at zero-bias. Absorption edge study of both MSM and p-i-n photodetectors, based on device spectral responses, resulted in a performance comparison of MSMs and p-i-ns, as the solar-blind photodetection requires a sharp solar-blind rejection. Photoconductive detectors and avalanche photodetectors, with the internal gain advantage, have been discussed as well. A 30μm diameter GaN avalanche photodiode achieved a gain >23, with a dark current less than 100pA. The breakdown showed a positive temperature coefficient of 0.03 V/K that is characteristic of avalanche breakdown. SiC APDs, as candidates for visible-blind applications, have been designed, fabricated and characterized. An avalanche gain higher than 10⁵, with a dark current less than 1nA, showed the potential of SiC APD replacing PMTs for high sensitivity visible-blind UV detection. A silicon-based optical receiver has been presented in the Appendix. With the photodiode internal avalanche gain ~4, a sensitivity ~-6.9dBm at 10Gbps has been achieved. / text
12

Discrete-time Stochastic Analysis Of Land Combat

Eliiyi, Ugur 01 January 2004 (has links) (PDF)
In this study, we present the implementation and experimental analysis of a modeling approach for analyzing tactical level land combat to generate information for weapon and ammunition planning. The discrete-time stochastic model (DSM), which can handle small and moderately large force levels, is based on single shot kill probabilities. Forces are assumed to be heterogeneous on both sides, and both directed and area fire types are modeled by means of combinatorial analysis. DSM considers overkills and can handle noncombat loss and engagement processes, discrete reinforcements, force combinations and divisions. In addition to experimenting with DSM, we estimate attrition rate coefficients used in Lanchester combat models, such that the two models will yield similar figures for force levels throughout the combat.
13

Applications of Artificial Intelligence in Military Training Simulation

Golovcsenko, Igor V. 01 January 1987 (has links) (PDF)
This report is a survey of Artificial Intelligence (AI) technology contributions to military training. It provides an overview of military training simulation and a review of instructional problems and challenges which can be addressed by AI. The survey includes current as well as potential applications of AI, with particular emphasis on design and system integration issues. Applications include knowledge and skills training in strategic planning and decision making, tactical warfare operations, electronics maintenance and repair, as well as computer-aided design of training systems. The report describes research contributions in the application of AI technology to the training world, and it concludes with an assessment of future research directions in this area.
14

Bradford Non-Lethal Weapons Research Project (BNLWRP). Occasional Paper No. 1. The Early History of "Non-Lethal" Weapons.

Davison, N. January 2006 (has links)
Yes / This paper explores the early history of ¿non-lethal¿1 weapons development covering the period from the 1960¿s, when several diverse weapons were first grouped together in one category and described as ¿non-lethal¿ by law enforcement end-users and policymakers, until 1989, just before the hugely increased interest in the field that developed during the 1990¿s amongst both police and military organisations. It describes the origins and emergence of new weapons, examining this process with reference to technological advances, wider socio-political context, legal developments, and evolution of associated institutional structures. Developments in both the policing and military spheres are considered as well as the interconnections between them. Necessarily this paper focuses on events in the US2, in part because it led the way in this field but also because sources of information on US activities are more readily available.3.
15

Bradford Non-Lethal Weapons Research Project (BNLWRP). Occasional Paper No. 3. The Contemporary Development of ¿Non-Lethal¿ Weapons.

Davison, N. January 2007 (has links)
yes / This is the third in a series of Occasional Papers published by the Bradford Non-Lethal Weapons Research Project. It addresses the contemporary development of anti-personnel ¿non-lethal¿1 weapons, covering the period from 2000 to 2006 inclusive2 and focusing on the research and development programmes of the US Department of Defense and Department of Justice. Following Occasional Paper No. 1, The Early History of "Non-Lethal" Weapons,3 and Occasional Paper No. 2, The Development of ¿Non-Lethal¿ Weapons During the 1990¿s,4 this paper completes our analysis of the overall development of ¿non-lethal¿ weapons from their inception up to the present day.
16

Explosive emission cathodes for high power microwave devices: gas evolution studies

Schlise, Charles A. 06 1900 (has links)
Approved for public release, distribution is unlimited / Present-day high power microwave devices suffer from a lack of reliable, reproducible cathodes for generating the requisite GW-level electron beam in a vacuum. Standard explosive emission cathode pulse durations have been limited to 10's or 100's of ns due to the expansion of cathode-generated plasma and the ensuing impedance collapse that debilitates microwave output. Traditional thermionic cathodes do not suffer from this drawback of plasma generation, but have not yet been able to provide the required emission current densities explosive emission cathodes are capable of. It is expected that if the plasma could be made cooler and less dense, explosive emission would be more stable. Cesium iodide (CsI) has been found to slow the impedance collapse in many explosive emission cathodes. Herein we will experimentally examine diode impedance collapse, gas production, and cathode conditioning in an effort to perform an evaluation of explosive cathode performance in a typical thermionic electron gun environment. These results will then be used to help demarcate the parameter space over which these CsI-coated carbon fiber cathodes are viable candidates for the electron beam source in next-generation high power microwave devices. / Lieutenant, United States Navy
17

Monitoring the progress of the Navy Marine Corps Intranet (NMCI) implementation, performance and impact

Dalaklis, Dimitrios 03 1900 (has links)
Approved for public release, distribution is unlimited / Information Superiority is the driver for the creation of the Global Information Grid (GIG) as the mean to provide connectivity between all parts of shore establishments, and with all deployed forces at sea and ashore. The Navy Marine Corps Intranet (NMCI) is an information technology (IT) services contract to provide to provide secure universal access to integrated voice, video and data communications; eliminate interoperability problems and remove network impediments to improve productivity and speed of command to the shore-based components of the Navy and Marine Corps. The NMCI contract is the procurement of IT services based on a commercial model of Service Level Agreements (SLAs). Under this model, the emphasis is placed on the verification, validation, and monitoring of the end-user services and not on the underlying infrastructure of systems. The research explores the current implementing effort of NMCI and analyzes the way this common network capability is tested and monitored. This thesis will provide a single source of information for managers seeking to quickly understand the impact of NMCI as an enterprise level asset. Security policies related to the project are examined and recommendations to improve this new IT initiative are made. / Lieutenant, Hellenic Navy
18

User interface design and evaluation of a shipboard electronic warfare console

Miller, Richard H. 24 October 2005 (has links)
This research tested the effect of unique combinations of interface coding and presentation techniques for the redesign of the AN/SLQ-32(V) Display Control Console (DCC). The DCC provides Navy operators with bearing and threat information for radar emitters. The task of emitter identification was used to test potential redesigns. There is no research to substantiate the current or possible redesign solutions. Thus, Experiment 1 tested potential design modifications for the DCC. The factorial combination of the following comparisons yielded eight possible design solutions: color versus monochrome coding, polar (bearing only) versus range (bearing and range) presentation, and geometric symbols versus icons. Each design was tested in three conditions of emitter density: low, medium, and high. Researchers have evaluated color and symbology with consideration to emitter display systems, but without considering how range information and emitter density effect performance. Results indicate that range information improves performance by 60%. The addition of color and the new icons also significantly improves performance (17% and 15%, respectively) as compared to the current DCC configuration (Polar, Geometric, and Monochrome). Performance was measured by time to complete a task, errors, and subjective workload. Experiment 2 considered redesign solutions not restricted to the existing hardware or software. Although discussed frequently in the interface literature, performance differences between direct-manipulation and command-key interfaces have not been validated. In this study, two interfaces were constructed to take advantage of direct manipulation and command-key interaction (DMI and CKI, respectively) styles while adding a computer-aided emitter library management system, an on-screen oscilloscope, a polygon display of emitter parameters, range information, icons, increased usage of color, and other design changes. Results indicate no differences between the CKI and DMI for the time required to perform the task or for subjective workload. Although both interfaces were designed to take advantage of their respective features, operators did not perform faster with the CKI than with the DMI. However, operators did have significantly fewer errors with the DMI than with the CKI. When compared to the existing DCC and the Range/Color/Iconic design, operators using the CKI and DMI: (1) processed twice as many emitters, (2) reduced one type of error by 50% (CKI) or 67% (DMI), (3) reduced a second type of error to zero, (4) decreased subjective workload by over 50%, and (5) maintained a higher level of performance regardless of emitter density. / Ph. D.
19

Multiple beam directors for naval free electron laser weapons

Mitchell, Ethan D. 03 1900 (has links)
Approved for public release, distribution is unlimited / The Free Electron Laser has the potential to become a revolutionary weapon system. Deep magazines, low cost-per-shot, pinpoint accuracy, and speed of light delivery give this developing weapon system significant advantages over conventional systems. One limiting factor in high energy laser implementation is thermal blooming, a lensing effect which is caused by the quick heating of the atmosphere, so that the laser beam does not focus on the desired spot, thereby degrading the effectiveness of the laser on target. The use of multiple beam directors focusing on a target from a single platform may mitigate thermal blooming by allowing half of the laser's energy to travel through a given volume of air, so that they only overlap very near the target. Less energy traveling through a given volume of space means less heating, and therefore lessens the effects of thermal blooming. Also, simulations of FEL's were conducted modifying parameters such as the number of undulator periods, electron beam focus, the normalized Rayleigh length, and mirror output coupling, in order to determine optimum design parameters. New parameters for the next proposed FEL were simulated to examine the effect of mirror tilt on laser power and extraction as well. / Lieutenant, United States Navy
20

Analyzing the feasibility of using secure application integration methodology (SAIM) for integrating don enterprise resource planning (ERP) application

Marin, Ramon O. 03 1900 (has links)
Approved for public release, distribution is unlimited / A thorough examination of the Secure Application Integration Methodology (SAIM) for applicability in the Department of the Navy (DON) would provide useful information about a beneficial methodology. SAIM is analyzed, by accessing its step by step directions, for suitability in the integration of the Enterprise Resource Planning (ERP) projects implemented by the SYSTEMS COMMANDS (SYSCOMS). The Navy Enterprise Convergence Team (NECT) that leads the ERP integration effort could benefit from a sound Enterprise Application Integration methodology. Results do not support SAIM as the sole guiding EAI methodology however it could have some value to the NECT. SAIM has three primary benefits which NECT could employ: 1) It provides a complete walkthrough of the EAI process, 2) It emphasizes the importance of an Enterprise Architecture, and 3) It provides useful management checklists along with other important considerations. SAIM also has some significant shortcomings: 1) It does not support all the DON Chief Information Officer requirements, 2) It does not provide Change Management Guidance, 3) It does not take into account the uniqueness of the Navy's environment, and finally 4) SAIM relies on an Enterprise Architecture as its foundation which the Navy does not currently have. / Lieutenant Commander, United States Navy

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